Bluetooth: move AIDL files related to Bluetooth into system/bt (2/3)

This patch moves *.aidl files from
frameworks/base/core/java/android/bluetooth into system/bt/binder. This
is in preparation to convert the Bluetooth deamon into native
implementation piece by piece.
In order to do that, one must have C++ header files, and paths to them
with AIDL files, and */java/* folder didn't seem as proper place for
that. Additionally, keeping AIDL files out of framework/base will not
require creating dependency on this huge project, which should help
keeping the compilation fast.

Test: compilation test
Change-Id: I4c992e6ee16eea3173a49b1d37e961af3d3c9ac6
Merged-In: I4c992e6ee16eea3173a49b1d37e961af3d3c9ac6
(cherry picked from commit 8a12de49177a341a118c95435177fba4f12fe412)
diff --git a/Android.bp b/Android.bp
index 462b8be..91ee232 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1,4 +1,5 @@
 subdirs = [
+    "binder",
     "build",
     "btif",
     "btcore",